Risk for gastrointestinal adverse events in the form of nausea, vomiting, diarrhoea and constipation motivates vigilance against insufficient intake of food, especially of carbohydrate.

Common adverse reactions of eribulin that can be confused with an acute porphyric attack are nausea, vomiting diarrhoea and constipation. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

Eribulin is not an inducer or mechanism-based inhibitor of any major CYP enzymes, and therefore no pharmacokinetic porphyrinogenic effects are suspected.

Eribulin is a furopyran, a structurally simplified synthetic analogue of halichondrin B which is a natural product isolated from the marine sponge Halichondria okadai.

Eribulin is an antineoplastic agent indicated for the treatment of adult patients with locally advanced or metastatic breast cancer and for adult patients with unresectable liposarcoma. It is administered intravenously.

Eribulin is a substrate of CYP 3A4, but up to 70 per cent of the administered dose is eliminated unchanged through biliary excretion. Eribulin does not inhibit the CYP enzymes CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6 or 2E1 at relevant clinical concentrations, but is described as a mild inhibitor of CYP 3A4 (SPC). In an in vitro study eribulin did not induce CYP3A expression or activity but showed some potential for inhibition of CYP3A4-mediated metabolism as a substrate competitor. This reversible inhibition was determined to be not clinically relevant, based on the enzyme-kinetic characterization and the lack of NADPH- and time-dependent enzyme inhibition (Zhang 2008). No in vivo drug-drug interaction studies have been carried out.